Convert parent image specification to image_spec calls

Change-Id: I1f1ba1833dace69f7c6746c74d737cfb3807a884
Depends-On: I18281bdb41e91cd5c9160055f1617d7ee9d3b548

docker/neutron-base/Dockerfile.j2

@@ -1,4 +1,4 @@
-FROM {{ namespace }}/openstack-base:{{ tag }}
+FROM {{ image_spec("openstack-base") }}
 MAINTAINER {{ maintainer }}
 
 RUN apt-get -y install --no-install-recommends \

docker/neutron-dhcp-agent/Dockerfile.j2

@@ -1,2 +1,2 @@
-FROM {{ namespace }}/neutron-base:{{ tag }}
+FROM {{ image_spec("neutron-base") }}
 MAINTAINER {{ maintainer }}

docker/neutron-l3-agent/Dockerfile.j2

@@ -1,4 +1,4 @@
-FROM {{ namespace }}/neutron-base:{{ tag }}
+FROM {{ image_spec("neutron-base") }}
 MAINTAINER {{ maintainer }}
 
 RUN apt-get -y install --no-install-recommends \

docker/neutron-metadata-agent/Dockerfile.j2

@@ -1,4 +1,4 @@
-FROM {{ namespace }}/neutron-base:{{ tag }}
+FROM {{ image_spec("neutron-base") }}
 MAINTAINER {{ maintainer }}
 
 COPY neutron_sudoers /etc/sudoers.d/neutron_sudoers

docker/neutron-openvswitch-agent/Dockerfile.j2

@@ -1,2 +1,2 @@
-FROM {{ namespace }}/neutron-base:{{ tag }}
+FROM {{ image_spec("neutron-base") }}
 MAINTAINER {{ maintainer }}

docker/neutron-server/Dockerfile.j2

@@ -1,4 +1,4 @@
-FROM {{ namespace }}/neutron-base:{{ tag }}
+FROM {{ image_spec("neutron-base") }}
 MAINTAINER {{ maintainer }}
 
 USER neutron

docker/openvswitch-base/Dockerfile.j2

@@ -1,4 +1,4 @@
-FROM {{ namespace }}/base-tools:{{ tag }}
+FROM {{ image_spec("base-tools") }}
 MAINTAINER {{ maintainer }}
 
 RUN apt-get -y install --no-install-recommends \

docker/openvswitch-db/Dockerfile.j2

@@ -1,2 +1,2 @@
-FROM {{ namespace }}/openvswitch-base:{{ tag }}
+FROM {{ image_spec("openvswitch-base") }}
 MAINTAINER {{ maintainer }}

docker/openvswitch-vswitchd/Dockerfile.j2

@@ -1,3 +1,3 @@
-FROM {{ namespace }}/openvswitch-base:{{ tag }}
+FROM {{ image_spec("openvswitch-base") }}
 MAINTAINER {{ maintainer }}